The latest developments of the 3GPP standards are referred to as the Long Term Evolution (LTE) of EPC (Evolved Packet Core) network and E-UTRAN (Evolved UMTS Terrestrial Radio Access Network). Under the 3GPP standards, a NodeB (or an eNB in LTE) is the base station via which mobile communications devices connect to a core network and communicate with other communications devices or remote servers. For simplicity, the present application will use the term base station to refer to any such base stations. Communications devices might be, for example, mobile communications devices such as mobile telephones, smartphones, user equipment (UE), personal digital assistants (PDAs), laptop computers, web browsers, and the like. 3GPP standards also make it possible to connect non-mobile user equipment to the network, such as Wi-Fi routers, modems, which can be implemented as a part of a (generally) stationary apparatus. For simplicity, the present application refers to mobile telephones in the description, but it will be appreciated that the technology described can be implemented on any mobile and “non-mobile” equipment that can connect to such a core network.
LTE also allows mobile telephones to connect to the core network using ‘non-3GPP’ access technologies as well, such as Wi-Fi (based on the Institute of Electrical and Electronics Engineers' (IEEE) 802.11 family of standards), WiMAX (based on the IEEE 802.16 family of standards), and the like. A list of supported access technologies is published in the 3GPP TS 23.402 standards document.
A Mobility Management Entity (MME) in the core network manages the connections of the mobile telephones with the core network. When a mobile telephone attaches to the LTE network via a base station, the MME sets up a default Evolved Packet System (EPS) Bearer between the mobile telephone and a gateway in the core network. An EPS Bearer defines a transmission path through the network and assigns an IP address to the mobile telephone to be used by the mobile telephone to communicate with remote servers or other communication devices. An EPS Bearer also has a set of data transmission characteristics, such as quality of service, data rate and flow control parameters, which are defined by the subscription associated with the mobile telephone and are established by the MME upon registration of the mobile telephone with the network.
The EPS Bearer is thus managed by the MME, which signals to the mobile telephone when it needs to activate, modify, or deactivate a particular EPS Bearer. Thus there are two connections between the mobile telephone and the communication network: one for the user data transmitted using the established EPS bearer (also known as the user plane) and another one for managing the EPS Bearer itself (also known as the control plane).
The so-called Non-Access Stratum (NAS) protocols form the highest stratum of the control plane between the mobile telephone and the MME. NAS protocols support a mobility of the mobile telephone and session management procedures to establish and maintain IP connectivity between the mobile telephone and a PDN GW (Packet Data Network Gateway). The Evolved Packet System (EPS) offers “ready-to-use” IP connectivity and “always-on” features to compatible mobile telephones. The NAS protocols include e.g. the EPS Mobility Management (EMM) and EPS Session Management (ESM) protocols. The EMM protocol provides NAS security and mobility control for the mobile telephones in the E-UTRAN, whilst the ESM protocol provides procedures for the handling of EPS bearer contexts.
The mobile telephone needs to register with the communications network (or communications system) in order to receive packet data services and/or other services requiring registration. This registration is also known as ‘network attachment’ and is described in more detail in section 5.3.2 of the 3GPP TS 23.401 standard, the contents of which are incorporated herein by reference. The mobile telephone can benefit from always-on IP connectivity by establishing a default EPS bearer during network attachment. The attach procedure may also trigger establishment of one or more dedicated EPS bearer(s). During the attach procedure, the mobile telephone also receives an IP address from the network.
During the attach procedure, the mobile telephone provides its unique identifier, e.g. a ‘Mobile Equipment Identity’ (IMEI) to the MME. The MME passes the obtained identifier to the home subscriber server (HSS) and to the packet data network gateway (PDN GW or P-GW) serving this mobile telephone.
Typically, a number of gateways are provided between the communications network and the external computer network(s), such as the public Internet, that the mobile telephone is allowed to access. Different gateways may be employed, for example, to provide access to different networks and/or to different services and/or for load balancing purposes. Different gateways are also provided in different operator networks (PLMNs). Each gateway may be identified by its name, which is often referred to as the Access Point Name (APN). The APN is used in other 3GPP data access networks, e.g. general packet radio service (GPRS) networks (2g) or Wideband Code Division Multiple Access (W-CDMA) networks (3g).
In order to establish a packet data connection with an external network, a mobile telephone must be configured with an APN to use when requesting a connection. The communication network will then examine this identifier to determine the type of data connection to be created. Using this identifier, the communications network may also determine, for example, an IP address to be assigned to the mobile telephone, a security method to be used, whether or not a connection to a private network is to be created, and so on.
More specifically, based on the APN the communications network identifies the packet data network that the mobile telephone attempts to communicate with. In addition to identifying the PDN itself, an APN may also be used to define the type of service provided by the PDN, e.g. a multimedia messaging service (MMS), a file sharing service, a social networking service, a video streaming service, and the like.
However, the network operator may enforce barring of packet data services for its subscribers. Such barring is referred to as ‘operator determined barring’ (ODB) and may be applicable to either all or a sub-set of all APNs. The network operator may at any time activate/deactivate this feature by appropriately configuring the HSS data for the particular subscriber. Activation of ODB results in termination of any relevant services in progress, and barring of future requests for service covered by the barring category.
For example, certain subscribers (i.e. their mobile telephones) may be barred from using any packet data services at all, e.g. as specified by their subscription with the network operator. Alternatively, a mobile telephone may be allowed access to some specific APNs only (e.g. APNs providing a specific type of packet data service and/or operated by a specific service provider) while being barred from accessing all other APNs. For example, a mobile telephone may be barred from requesting packet data services from access points that are located within a visited network (VPLMN) whilst the mobile telephone is roaming away from their home network (HPLMN) (whilst use of APNs in the HPLMN may be still allowed).
When barring of access to all except some specific APNs is invoked in the HSS, the HSS updates the subscription profile of that user to contain only the specific non-barred APNs as ‘subscribed APNs’ and indicates the updated subscription information to the MME. This will allow the MME to enforce barring of packet data connections for each mobile telephone appropriately.
In particular, when the MME receives a request for PDN connectivity (e.g. a ‘PDN Connectivity Request’) from a mobile telephone, it checks whether or not the requested APN is included in the list of subscribed APNs for that subscriber. If the requested APN is included, then the MME continues with the PDN connectivity procedures and configures the requested packet data service for the mobile telephone. However, if the APN is not included in the list provided by the HSS, then the MME rejects the PDN connectivity request (e.g. by sending a ‘PDN Connectivity Reject’ response) and provides an appropriate rejection cause to the mobile telephone. Furthermore, when the MME receives the list of subscribed APNs for a subscriber, it checks whether the subscriber's mobile telephone has any existing PDN connection via APNs that are not included in the list of subscribed APNs; and if there are, then the MME also deactivates the packet data services that are being provided via an APN that is not included in the list of subscribed APNs and indicates an appropriate rejection cause to the mobile telephone.
Further details of the technical realization of ODB are described in version 11.1.0 of the 3GPP TS 23.015 standard, which is incorporated herein by reference.
In summary, the establishment of a packet data connection whilst ODB is in place may be rejected by the network (i.e. the MME) either due to mobility reasons (e.g. during roaming) or due to session related reasons (e.g. requested service or gateway) by using either EMM or ESM signalling, respectively.